Within the field of cutting tools used in threading operations, exchangeable anvils or shims directly supporting a removably securable threading insert have long since provided a way to adjust the inclination angle of the threading insert to equal the helix angle of the thread being cut, and thus provide equal clearance for the cutting edges.
U.S. Pat. No. 3,520,042 discloses an adjustable holder for a thread cutting insert which eliminates the need for exchangeable anvils or shims. The adjustable holder comprises a shank with a recess in the form of a partial cone, and a mating partially conical block disposed in the recess. The thread cutting insert is mounted on the conical block by means of a set screw, and the conical block is angularly adjustable within the recess so as to provide alignment between the plane of symmetry of the cutting insert and the helix angle of the thread being cut. A slot in the shank is angularly aligned with a radial threaded bore in the conical block, and a bolt located in the slot engages the threaded bore to clamp the conical block in the recess at its adjusted position.
US 2008/0253847 discloses a tool holder assembly which incorporates a cutting edge adjustment member that does not contact the cutting insert. The tool holder assembly also includes a tool holder and an insert holder, with the cutting insert being mounted in the insert holder by a screw and a clamp, and an outside curved surface of the insert holder configured to mate with a curved arcuate surface of an insert receiving end of the tool holder. The cutting edge adjustment member is in the form a precision ground adjustment washer having an angled top surface. An adjustment bolt, having a head that rests on the angled top surface of the adjustment washer, protrudes through a slot in the insert receiving end and engages a threaded hole in the insert holder. The angle of the top surface determines the rotational position in the slot at which the bolt engages the threaded hole and thus defines a particular cutting edge angle. The adjustment washer can be re-oriented or exchanged for another adjustment washer with different angle of top surface to define a different cutting edge angle.
It is an object of the present invention to provide an improved adjustable cutting tool.
It is also an object of the present invention to provide an adjustable cutting tool without exchangeable anvils or shims.
It is a further object of the present invention to provide an adjustable cutting tool without separate shank and insert holder components.
It is yet a further object of the present invention to provide an adjustable cutting tool having a readily accessible and operator friendly means of adjustment.